Hybrid Electric Vehicle Vibration Control Using Walsh-Based Discrete Fourier Transform
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Solution Overview
Problem
Conventional frequency analysis methods for hybrid electric vehicles fail to clearly distinguish engine vibrations from noise components, leading to excessive vibration suppression control that negatively affects control efficiency and energy management, and are unable to actively control vibrations across multiple frequency components.
Innovation Solution
The method employs Walsh-based Discrete Fourier Transform (WDFT) to calculate engine speed, set reference angles, and select control target frequencies, generating a reference signal to control motor torque and reduce vibration, thereby reducing the controller's calculation load and improving energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional frequency analysis using bandpass filter is used, then vibration component extraction is performed, but engine vibration and noise components are not clearly divided leading to excessive vibration suppression control
Solution Approach 1:
The patent changes the fundamental parameter of frequency analysis from conventional bandpass filtering to Walsh-based Discrete Fourier Transform (WDFT). This parameter change enables clear separation of engine vibration components from noise components by utilizing Walsh functions that are synchronized with engine rotation, achieving precise vibration extraction without excessive suppression control
2Reliability
If conventional frequency analysis with specific frequency reference signal is used, then synchronization signal is generated for specific frequency component, but active vibration control of other frequency components cannot be performed
Solution Approach 1:
The patent applies universality by designing the WDFT system to simultaneously handle multiple frequency components. The Walsh-based transform can extract vibration signals at fundamental frequency and harmonic frequencies (1x, 2x, 3x engine order) using the same transformation framework, enabling the control system to generate synchronized reference signals for multiple frequency components and actively control vibrations across the entire frequency spectrum
3Object-affected harmful factors
If comprehensive vibration suppression control is applied, then all vibration components are suppressed, but calculation load of controller increases
Solution Approach 1:
The patent segments the vibration control problem by identifying and targeting only the significant frequency components (fundamental frequency and selected harmonics) rather than attempting to suppress all frequency components. The WDFT enables selective extraction of vibration components at specific frequencies, allowing the controller to focus computational resources on generating reference signals only for the most impactful vibration frequencies, thereby reducing overall calculation load while maintaining effective vibration suppression
Data Source
AI summary
Disclosed are a method of and an apparatus for controlling a vibration of a hybrid electric vehicle. An apparatus for controlling a vibration of a hybrid electric vehicle may include: an engine position detector detecting a position of an engine; an air amount detector detecting an air amount flowing into the engine; an accelerator pedal position detector detecting a position of an accelerator pedal; a vehicle speed detector detecting a speed of the hybrid electric vehicle; and a controller. The controller controls operation of a motor based on the position of the engine, the air amount, the position of the accelerator pedal, and the speed of the hybrid electric vehicle.